The present invention relates to a filler neck for the fuel tank of a motor vehicle, having a housing with an outer closure which can be pivoted into the closed and open position, and having a second closure element which is accommodated in the housing interior and is operatively connected to a ventilating valve, which, in the event of excess pressure in the fuel tank, is automatically opened, for the purpose of equalizing the pressure, and, when the fuel nozzle which swivels open the closure element is introduced, is opened via the operative connection.
A filler neck of this type is disclosed, for example, in WO 99/03697. This filler neck is one in which, contrary to the designs which are generally customary, a closure which can be removed during opening and can be screwed, in particular, to the filler neck is not provided. In the case of the customary filler necks having separate closures of this type, there is the risk of the user, after the refueling, forgetting to screw the tank closure on again, and of the closures, which are generally placed on the motor vehicle, becoming lost. Then, firstly, dirt can pass from outside into the interior of the tank and, secondly, fuel vapors can escape from the tank.
The filler neck disclosed in WO 99/03697 does not have these disadvantages, since the outer closure is mounted in a manner such that it can be swiveled open and shut on the filler neck itself. This closure is designed in terms of structure in such a manner that, when the closure is closed, air can pass from the outside into the interior through a filter element and from the inside fuel vapors can also escape to the outside. Moreover, this filler neck is provided with a ventilating valve and with a second closure element which is mounted pivotably further inward in the housing of the filler neck. This closure element ensures, in its closed position, a gas-tight seal between the fuel tank on the one side and the filler-neck interior remaining toward the outer closure. If a negative pressure arises in the interior of the tank during the consumption of the fuel, the second closure element can automatically open somewhat, with the result that ambient air can flow into the interior of the tank in order to equalize the pressure. This is ensured via an actuating arm which acts on the closure element and is operatively connected to a comparatively weak spring. If a certain excess pressure arises in the fuel tank, it is ensured that the ventilating valve opens automatically. The ventilating valve is also opened during introduction of the fuel nozzle when the latter, as it is being introduced, swivels open the second closure element. This ensures the required ventilation of the tank when the fuel is being put in. This known filler neck has been well thought through with regard to its functioning and its structure. After the refueling, after the fuel tank has been filled, a little fuel often remains in the interior above the second closure element and collects in particular on the outer side of this closure element. If the fuel nozzle is fully introduced again for renewed filling of the tank, the second closure element is, as explained above, pressed by the fuel nozzle into the open position, in which case the slight excess pressure of the fuel vaporxe2x80x94about 0.15 bar excess pressurexe2x80x94prevailing in the region within the closure element causes the collected fuel residues to spray out of the filler nozzle. This is unpleasant for the person carrying out the refueling.
The invention has therefore been set the object of improving the known filler neck in this regard and, by means of a simple measure, of ensuring that fuel residues are prevented from spraying out.
According to the invention, the object which has been set is achieved in that a lever is provided, which lever is mounted pivotably on the housing and, actuated by the fuel nozzle when the latter is introduced, opens the ventilating valve even before the fuel nozzle swivels open the inner closure element.
The invention therefore ensures that the slight excess pressure prevailing in the interior of the tank is already reduced before the inner closure element is opened. This effectively prevents residual fuel which is situated above the second closure element from spraying out.
In this connection, the ventilating valve of the filler neck is, as known per se, designed in such a manner that it has a valve part which can be displaced counter to spring force. In order to open the ventilating valve via an actuation of the lever by the fuel nozzle, provision is made for the lever to have two lateral actuating arms which grip under guide parts provided on the valve part. This solution does not have any effect on the other functions of the filler neck; it is simple in terms of structure and can be accommodated, also in a simple manner, in the region of the ventilating valve.
The guide parts provided on the valve part are inwardly directed extensions of tabs provided to the side of the valve part. This structure also ensures that the guide parts cannot have any adverse effect on the other functions and actions of the filler neck. Moreover, these guide parts at the same time form an installation aid by keeping the relatively weak springs which act upon the actuating rod in a tensioned position during fitting of the valve and of the components interacting with said valve.
Furthermore, the ventilating valve is to be completely opened by the inner closure element being swiveled open by the fuel nozzle. A slight opening of the ventilating valve is sufficient in order to compensate for the slight excess pressure in the interior of the tank. For this purpose, those regions of the actuating arms of the lever which interact with the guide parts of the valve part are designed as radial cams which ensure the desired, slight opening.
In order, after the fuel nozzle has been removed, to bring the additional lever back into its starting position and to keep it there, the lever is appropriately acted upon by a spring.